This invention relates generally to the corrugated board industry and, more particularly, relates to a corrugated board scoring head having a scoring edge having a curvilinear nib profile.
For many decades, scoring heads have been used to impress score lines into corrugated board to facilitate folding the board into desired configurations, such as boxes. Proper score lines should be xe2x80x9ccrispxe2x80x9d in that the board immediately adjacent to the score line is not bent or rolled toward the score line. In addition, the scoring head should not tear, crack or cut the top liner of the board. A board with a xe2x80x9crolledxe2x80x9d score line or torn, cracked or cut liner is weaker than a board with a crisp score line, and may be considered defective for many applications.
Despite many years of industry experience, conventional scoring heads still produce an unacceptable number of defective xe2x80x9crolledxe2x80x9d score lines and torn, cracked or cut liners. These problems can be accentuated when the same scoring head is used to score corrugated board of varying thickness, such as single-wall, double-wall and triple-wall board. For example, a scoring head that effectively creates crisp score line in double-wall board may produce rolled score lines in single-wall board. Conversely, a scoring head that effectively creates create crisp score lines in single-wall board may tear, crack or cut the top liner when used on double-wall board. In general, a single scoring head that effectively creates crisp score lines in single-wall, double-wall and triple-wall board is not presently available. For this reason, the scoring heads often must be changed in response to changes in board thickness. Of course, changing the scoring heads, which slows production, is inconvenient and costly.
Therefore, there is a continuing need in the corrugated board industry for a scoring head that consistently creates crisp score lines in corrugated board of varying thickness, such as single-wall, double-wall and triple-wall board.
The present invention meets the needs described above in a scoring edge having a curvilinear nib profile. The scoring head may be symmetrical about a central axis. The curvilinear nib profile of the scoring head allows the head to consistently create crisp score lines in corrugated board of varying thickness, such as single-wall, double-wall and triple-wall board. That is, the curvilinear nib scoring head profile effectively avoids tearing, cracking or cutting the top liner, or creating rolled score lines, when used on corrugated board of varying thickness. Therefore, the same scoring head can be used to score single-wall, double-wall and triple-wall board.
Generally described, the invention includes a scoring head configured for impressing score lines into corrugated board. The scoring head includes an inner wheel portion and a scoring edge portion located at an outer edge of the inner wheel portion. The scoring edge, which is faired into the inner wheel portion, defines a curvilinear nib that is generally nipple shaped.
More specifically, the nipple shaped nib may include a base portion faired into the inner wheel portion. The nib may also include a bottle nose-shaped portion faired into the base portion. In addition, the scoring edge portion may include a central protuberance faired into the bottle nose-shaped portion of the nib.
Stated somewhat more specifically, the scoring head includes an inner wheel portion and a scoring edge portion located at an outer edge of the inner wheel portion and faired into the inner wheel portion. The scoring edge portion, when viewed in cross-section, includes a substantially axial tier located between two substantially radial sides. The scoring edge portion also includes a curvilinear nipple shaped nib faired into the radial sides of the axial tier and faired into the inner wheel portion.
Further defined, the nib may include a first arcuate segment extending about a first radius of rotation pointed in an axially inward and radially inward direction, and the radial side of the central protuberance may be faired into the first arcuate segment. The nib may include a second arcuate segment extending about a second radius of rotation pointed in an axially inward and radially outward direction, and the first arcuate segment is faired into the second arcuate segment. The nib may include a third arcuate segment extending about a third radius of rotation pointed in an axially inward and radially inward direction, and the second arcuate segment may be faired into the third arcuate segment. The nib may include a fourth arcuate segment extending about a fourth radius of rotation pointed in an axially outward and radially outward direction, and the fourth arcuate segment is faired into the third arcuate segment and faired into the inner wheel portion.
In various embodiments, the first radius of rotation may be smaller in magnitude than the fourth radius of rotation, the first radius of rotation may be smaller in magnitude than the second and third radii of rotation, the first and fourth radii of rotation are smaller in magnitude than the second and third radii of rotation. Alternatively, the first radius of rotation may be smaller in magnitude than the fourth radius of rotation, and the fourth radius of rotation may be smaller in magnitude than the second and third radii of rotation. Or the first radius of rotation may be smaller in magnitude than the fourth radius of rotation, and the fourth radius of rotation may be smaller in magnitude than the second radius of rotation.
The specific configuration of a preferred embodiment of the scoring head will become apparent from the following detailed description and the appended drawings and claims. Many other variations, which will be apparent to those skilled in the art, fall within the scope of the present invention as defined by the claims at the end of this specification.